Sortation system

ABSTRACT

A sortation conveyor has a plurality of pairs of slats which are generally aligned with each other and which define a portion of an upper conveying surface. A gap is defined between the slats of the pair which extends laterally. The gap may have an offset portion.

This application claims priority benefit of and incorporates byreference the disclosures of U.S. provisional patent application60/370,954 for End Cap For Sortation System Conveyor, filed Apr. 8,2002, U.S. provisional patent application 60/371,251 for Pusher ForSortation System, filed Apr. 8, 2002, U.S. provisional patentapplication 60/428,366 for Pusher For Sortation System, filed Nov. 22,2002, and U.S. provisional patent application 60/445,974 for SlatSortation Conveyor filed Feb. 7, 2003.

BACKGROUND OF THE INVENTION

The present invention relates generally to sortation conveyors, alsoknown as sorters, and their components, and is particularly directed topusher caps, pusher bases, pusher pads, conveyor slats and end caps forconveyor slats.

Sortation conveyors are used to sort items carried on a conveyingsurface by selectively diverting individual items on to laterallyextending spurs at the appropriate time. To accomplish this, pushershoes travel laterally (relative to the direction of travel of thesortation conveyor) to divert packages carried by the upper surface ofthe sortation conveyor to spurs. Pusher shoes are called by many names,including diverters, divert elements, pushers, and pusher elements.

A pusher shoe comprises an upper element, sometimes known as a pushercap, which is typically disposed above the upper surface of thesortation conveyor so as to divert packages located thereon, a pusherpad carried by the pusher cap to contact the packages, and a pusher basewhich carries the pusher cap and guides it along transverse slats whichcomprise the sortation conveyor

The transverse slats are typically arranged parallel to each other,perpendicular to the direction of travel. They are typically carried ateach end by a moving element, such as an endless chain. Frequently thechain will include alternately disposed extended pins which engage theslats, directly or indirectly so as to carry them.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention, andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIGS. 1A and 1B are perspective views of a pusher cap for a flat slattype sortation conveyor and a round tube type sortation conveyor,respectively, constructed in accordance with one aspect of the presentinvention.

FIG. 1C is a front view of either pusher cap of FIGS. 1A and 1B.

FIG. 2 is a top view of the pusher shoe shown in FIG. 1A.

FIG. 3 is a cross-sectional view of the pusher cap of FIG. 1A takenalong line 3-3 of FIG. 2.

FIG. 4 is a fragmentary perspective view of a plurality of pusher shoeswith the pusher cap of FIG. 1A, for a flat slat type sortation conveyor,shown aligned in a diverting arrangement.

FIG. 5 is a fragmentary top view of the pusher shoes illustrated in FIG.4.

FIG. 6 is an exploded perspective view of a pusher shoe of FIG. 4.

FIG. 7 is a bottom view of a pusher shoe of FIG. 4.

FIG. 8 is a bottom view of the pusher cap of FIG. 1A.

FIG. 9 is an enlarged fragmentary side view of a pusher shoe of FIG. 4,showing two overlapping pusher shoes mounted on a flat slat typeconveyor.

FIG. 10 is a side view of the pusher shoe shown in FIG. 4.

FIG. 11 is a perspective view of the ribbed side of the pusher pad shownin FIG. 10.

FIG. 12 is a fragmentary cross-sectional view of the pusher shoe of FIG.4, taken along line 12-12 of FIG. 5.

FIG. 13 is a perspective view of the back side of the pusher pad shownin FIG. 10.

FIGS. 14A and 14B are bottom and top views, respectively, of the pusherpad.

FIG. 15 is a top view of the pusher shoe shown in FIG. 1B.

FIG. 16 is a fragmentary perspective view of a plurality of pusher shoeswith the pusher cap of FIG. 1B, for a round tube type sortationconveyor, shown aligned in a diverting arrangement.

FIG. 17 is a fragmentary top view of the pusher shoes illustrated inFIG. 16.

FIG. 18 is an exploded perspective view of a pusher shoe of FIG. 16.

FIG. 19 is a bottom view of a pusher shoe of FIG. 16.

FIG. 20 is a bottom view of the pusher cap of FIG. 1B.

FIG. 21 is a fragmentary side view of the pusher shoes illustrated inFIG. 16.

FIG. 22 is a side view of the pusher shoe shown in FIG. 16.

FIG. 23 is a front perspective view of the end cap of FIG. 23.

FIG. 24 is a rear perspective view of the round tube end cap.

FIG. 25 is a front view of the end cap of FIG. 24.

FIG. 26A is a top view of the end cap of FIG. 24.

FIG. 26B is a rear, upside down view of the end cap of FIG. 24.

FIG. 27 is a side view of the end cap of FIG. 24.

FIG. 28 is a cross-sectional view of the round tube end cap taken alongline 28-28 of FIG. 25.

FIG. 29 is a cross-sectional view of the end cap of FIG. 23 taken alongline 29-29 of FIG. 25.

FIG. 30 is a perspective view of the bushing of the end cap of FIG. 23.

FIG. 31 is a front view of the bushing of the end cap of FIG. 23.

FIG. 32 is a side view of the bushing of the end cap of FIG. 23 inpartial cross-section taken along the center line of the bushing.

FIG. 33 is a front perspective view of another embodiment of an end capfor a round tube type conveyor according to another aspect of thepresent invention.

FIG. 34 is a rear perspective view of the end cap of FIG. 33.

FIG. 35 is a front view of the end cap of FIG. 33.

FIG. 36 is a rear view of the end cap of FIG. 33.

FIG. 37 is an exploded front perspective view of the end cap of FIG. 33and bushing.

FIG. 38 is a cross-section of the bushing and end cap of FIG. 37 takenalong the mid line of the bushing.

FIGS. 39 and 40 are top views of another embodiment of pusher shoesconstructed in accordance with another aspect of the present invention,showing 20° right hand and left hand pusher shoes, respectively.

FIGS. 41 and 42 are top views of pusher shoes similar to FIGS. 39 and40, showing 30° right hand and left hand pusher shoes, respectively.

FIG. 43 is a top view of the pusher cap shown in FIGS. 39 and 41.

FIG. 44 is a side view of the pusher cap of FIG. 43.

FIG. 45 is a bottom view of the pusher cap of FIG. 43.

FIG. 46 is a top view of the pusher pad shown in FIG. 39.

FIG. 47 is a side view of the pusher pad shown in FIG. 39.

FIG. 48 is a bottom view of the pusher pad shown in FIG. 39.

FIG. 49 is a perspective view of the pusher pad shown in FIG. 39.

FIG. 50 is a rear view of the pusher pad shown in FIG. 39.

FIG. 51 is a top view of the pusher pad shown in FIG. 41.

FIG. 52 is a side view of the pusher pad shown in FIG. 41.

FIG. 53 is a bottom view of the pusher pad shown in FIG. 41.

FIG. 54 is a perspective view of the pusher pad shown in FIG. 41.

FIG. 55 is a rear view of the pusher pad shown in FIG. 41.

FIG. 56 is an exploded perspective view of the pusher shoe of FIG. 41.

FIG. 57 is a side view of the pusher shoe of FIG. 39.

FIG. 58 is a fragmentary perspective view of a sortation conveyor andpusher shoes constructed in accordance with another aspect of thepresent invention.

FIG. 59 is a fragmentary plan view of the sortation conveyor and pushershoes of FIG. 58.

FIG. 60 is a side view of the sortation conveyor and pusher shoes ofFIG. 58 taken along arrow 60 of FIG. 58, with the closest end capsremoved.

FIG. 61 is a side view of a flight of two slats and a pusher shoe ofFIG. 60.

FIG. 62 is a fragmentary side view of adjacent flights of slats andpusher shoes of FIG. 60.

FIG. 63 is a cross-sectional side view of a pusher shoe of FIGS. 58-62taken along line 63-63 of FIG. 59.

FIG. 64 is an enlarged perspective view of the insert shown in FIG. 63.

FIG. 65 is an enlarged perspective view of the pin shown in FIG. 63.

FIG. 66 is a top perspective view of the pusher base shown in FIG. 60.

FIG. 67 is a bottom perspective view of the pusher shoe of FIG. 58.

FIG. 68 is a bottom perspective view of the pusher shoe of FIG. 58, froma different angle than FIG. 67.

FIG. 69 is a fragmentary side view of slat flights and pusher shoes ofFIG. 58.

FIG. 70 is a front perspective view of the end cap of the sortationconveyor of FIG. 58.

FIG. 71 is a rear perspective view of the end cap shown in FIG. 70.

FIG. 72 is a front view of the end cap shown in FIG. 70.

FIG. 73 is a rear view of the end cap shown in FIG. 70.

FIG. 74 is an cross-sectional perspective view of the end cap shown inFIG. 71, taken along line 74-74 of FIG. 73, and including a bushing notshown in FIG. 73.

Table 1 is a list of the material properties of Super Tough Nylon fromwhich the pusher caps and base may be made.

Table 2 is a list of the material properties of DuPont Dehrin Acetalfrom which the pusher bases may be made.

Table 3 is a list of the material properties of Santoprene® from whichthe pusher pads may be made.

Reference will now be made in detail to the present preferred embodimentof the invention, an example of which is illustrated in the accompanyingdrawings.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

Referring now to the drawings in detail, wherein like numerals indicatethe same elements throughout the views, FIG. 1A is a perspective view ofone embodiment of a pusher cap 2 a constructed in accordance with oneaspect of the present invention, configured for use on a flat slat typesortation conveyor. FIG. 1B is a perspective view of another embodimentof a pusher cap 2 b, similar to pusher cap 2 b but configured for use ona round tube type sortation conveyor. Since both pusher caps 2 a and 2 bare illustrated as right hand, 20° pusher caps, although it will beunderstood that the pusher caps may also be left hand or double sided,and have any divert angle, such as 30°. It will be noted that pushercaps 2 a and 2 b are constructed the same, except for being configuredfor different type sortation conveyors, pusher cap 2 a will be describedin detail with respect the common features of the two.

Referring also to FIGS. 1C and 2, pusher cap 2 a includes upper surface4 which presents a low profile (also referred to as a stealth profile)continuous surface that gradually merges with the upper edge ofgenerally vertical mounting surface 6. Pusher pad 38 (see FIG. 6) issecured to pusher cap 2 a at mounting surface 6. When pusher shoe 2 a isdiverted by the guide tracks (not shown) of the sortation conveyor,pusher pad 38 contacts packages carried by the upper surface (alsoreferred to as the conveying surface) of the sortation conveyor. Uppersurface 4 includes leading surface 4 a, center surface 4 b, top surface4 c, clearance surface 4 d and blend surface 4 e. Leading surface 4 aextends below the upper conveying surface of the sortation conveyor,merging into leading edge 8 a. Upper surface also includes surfaces 4 f,4 g and 4 h, which are generally coplaner, located on the side oppositemounting surface 6. These three surfaces terminate below the upperconveying surface of the sortation conveyor, at respective, generallyaligned edges 8 f, 8 g and 8 h. In the embodiment depicted, surfaces 4f, 4 g and 4 h are approximately 60 degrees from vertical, an angleselected to slide under a package so as to direct any package which mayencounter pusher cap 4 a on that surface up and over the upper surface4, so that there is not positive interference with the pusher shoeresulting from any such misplaced package.

As seen in FIG. 2, pusher cap 2 a is depicted as a 20° divert, righthand cap, with portion 6 a of mounting surface 6 being formed at anangle of about 20° relative to portion 6 b and the cap's longitudinaldirection of travel, thereby establishing the 20° angle of the divertwall (see FIGS. 4 and 5) when used with pusher pads of generally uniformthickness, as described below. Pusher caps 2 a and 2 b may be configuredwith a 30° divert angle, or any suitable divert angle, as well as lefthand or double sided caps.

The angle of leading surface 4 a is dictated by the location of leadingedge 8 a As seen in FIG. 9, the location of leading edge 8 a is setbelow the generally planar upper slat conveying surface 64 of thesortation conveyor. Leading surface 4 a inclines back therefrom at abouta 30 degree angle from horizontal. A corresponding angle is found on thetrailing edge 10 a to allow clearance between adjacent pushers wherethey overlap. The angle of leading surface 4 a allows enough wallthickness at 4 a′ based on the projection of leading surface 4 a up andback from leading edge 8 a.

Relative to the direction of travel of the conveying surface, pushersbasically have two longitudinal sides extending generally longitudinally(in the direction of conveyor travel) and two lateral sides extendinggenerally perpendicular to the direction of travel of the conveyor andgenerally parallel to the members, such as slats or tubes, that comprisethe conveying surface. Of the two longitudinal sides, one side is thedivert side having the pusher pad and functioning to divert items to thedesired locations. The other longitudinal side preferably is configuredso that there is not positive interference with the pusher shoeresulting from any such misplaced package which contact the pusher onthat side.

Referring to FIGS. 1A, 1B and 3, recessed surfaces 16 a and 16 b areformed in top surface 4 in between surfaces 4 f, 4 g and 4 h. Recessedsurfaces are steeper than the adjacent portion of surface 4 c from whichrecessed surfaces 16 a and 16 b extend, and than surfaces 4 f-h.Recessed surfaces terminate at edges 16 c and 16 d, which are disposedadjacent respective upper slat conveying surfaces 64. The locations andrelative angles of surfaces 16 a-b, 4 c and 4 f-h place recessedsurfaces 16 a and 16 b lower than adjacent portions of surfaces 4 c and4 f-h, inboard of edges 8 f-h, and inboard of the locations wheresurfaces 4 f-h extend below the upper slat conveying surfaces 64 of thesortation conveyor. With this “cow catcher” configuration, any packagewhich might encounter this longitudinal edge of a laterally movingpusher cap 2 a will engage surfaces 4 f-h, not edges 8 f-h or edges 16c-d, and will ride up and over pusher cap 2 a rather than pushedlaterally.

Top surface 4 c is generated from a polynomial curve, extending from theupper edges of surfaces 4 f-h, to the highest portion of the upper edgeof mounting surface 6. The only interruptions in the generallycontinuous upper surface, are the openings 20 in surface 4 for the boltsconnecting the pusher cap 2 a to the base (described below). Thecontinuous upper surface 4 presents minimum locations of sharp edges ordiscontinuous surfaces which could catch a mislocated package as theshoe slide there-past.

The angle of surfaces 4 b and 4 c are also dependant on or dictate thelocation of the interface between top surface 4 c and center surface 4b, which is located so as not to intersect any bolt holes 20.

Clearance surface 4 d provides clearance to avoid adjacent componentswhen the pusher shoe is at either end of the sortation conveyor, so thatpusher shoe stays within the desired clearance circle as the pushershoes travel around the drive or idler gear. Surface 4 e blends theadjacent surfaces to merge with the upper edge of mounting surface 6.

Referring to FIGS. 4 and 5, a plurality of pusher shoes with pusher cap2 a are shown being diverted, aligned to present a substantiallycontinuous divert wall formed from the plurality of overlapping, alignedpusher pads. As is well known, the pusher shoes are diverted by guidetracks (not shown) located under the sortation conveying bed, beingdiverted as appropriate to move packages to spur conveyors.

Referring to FIG. 6, the depicted embodiment of pusher shoe 22 includespusher cap 2 a and pusher base assembly 24. Pusher base assembly 24includes upper pusher base 26, lower pusher base 28, pusher base plate30, spacer 32, bearing 34 and pin 36. Two threaded fasteners 23respectively extend through holes 22 a and 22 c, aligned with respectiveopenings 20, through base 26 and threadingly engage lower pusher base28. A single bolt 25 extends through center hole 22 b of pusher cap 2 a,through bases 26 and 28, plate 30, through spacer 32 and bearing 34,threadingly engaging pin 36. Two additional screws 30 a extend throughthe two holes 30 b in plate 30, threadingly engaging lower base 28.Additional screws 26 a are inserted from the bottom of plate 26 throughholes 26 b and into holes 26 c (FIG. 9) in the underside of pusher cap 2a.

Pusher bases 26 and 28 may be made of any suitable material, such asDuPont Delrin Acetal, which provides low friction to accommodate thesliding motion of the pusher shoes, or super tough nylon. Bases 26 and28 may be formed as a single piece. Pusher caps described herein can bemade of any suitable material, such as super tough nylon. Pusher basesdescribed herein may also be made of any suitable material, such asDuPont Delrin Acetal or super tough nylon.

Pusher pad 38 is secured to cap 2 a by a plurality of tabs 40 whichextend into vertical slots 52 formed in pusher pad 38 (see FIGS. 11-12).Each tab 40 includes a ridge 40 a which engages a lip in the innersurface of the vertical slots of pusher pad 38 (see FIG. 12).

Referring to FIGS. 7 and 8, trailing surface 46 is an arcuate verticalwall, which comprises the rear edge of extension 48 of the pusher cap 2a which extends rearward beyond the edge of the trailing slat or tube.Extension 48 helps to control rotation of packages when engaged by thepusher during divert by providing a longer divert surface extendingbeyond the trailing edge of the flight of two slats, as can be seen inFIGS. 4, 5, 9 and 10.

As can be seen in FIGS. 7 and 8, a pattern of a plurality of ribs 50 areformed in the bottom of pusher cap 2 a. In the depicted embodiment, ribs50 have a wall thickness of approximately 0.100 inches, although theymay be of any appropriate wall thickness. Ribs 50 are arranged in arectangular pattern, approximately 90 degrees to each other. Ribs 50 aredisposed at an angle of approximately 45 degrees relative to thedirection of travel of the pusher shoe.

FIG. 9 illustrates adjacent pusher shoes with identical pusher caps 2 a,respectively, each carried by a flight 54 comprising leading slat 56 andtrailing slat 58. Slats 56 and 58 are connected together by end caps 60(omitted in FIG. 9) in a spaced apart relationship, defining guide path62 therebetween within which pusher base 28 travels. As can be seen inFIGS. 9 and 10, base 28 is shaped complementary to guide path 62. Inthis embodiment, slats 56 and 58 have identical shapes, being hollow andfilled with foam 57 to reduce noise. Each slat 56 and 58 comprises agenerally planar upper slat conveying surface 64 which, when disposed onthe top run of the sortation conveyor, collectively define upperconveying plane of the sortation conveyor, generally indicated by line66 in FIG. 9. Referring to slat 56 as an example, leading edge 56 a andtrailing edge 56 b are recessed below slat conveying surface 64 andconveying plane 66.

Referring also to FIG. 10, pusher cap 2 a includes portions 12, 14 and15 which extend below slat conveying surface 64 and conveying plane 66.Pusher pad 38 includes portions 38 a and 38 b which extend below slatconveying surface 64 and conveying plane 66, adjacent, but notnecessarily touching or coextensive with portions 12 and 14. Recesses 44a and 44 b, formed between portions 12, 14 and 15, accommodate theconfiguration of slat conveying surface 64, aligned with edges 16 c and16 d at the opposite side of pusher shoe 2 a.

Locating the outer edges of the pusher shoe below slat conveying surface64 and conveying plane 66 prevent pinching of flat items or the catchingof a package edge by such pusher shoe edges. Although any appropriateheight may be used, the overall height of pusher cap 2 a, in thedepicted embodiment, from the highest part of vertical mounting surface6 to the bottom of extensions 12 and 14 is 1.6875. In the depictedembodiment, the highest part of vertical mounting surface 6 is 1.5inches above slat conveying surface 64 and conveying plane 66. Thisheight is selected to provide adequate engagement between packages andthe pusher shoe, yet allow mislocated packages to slip up and over theshoe.

FIG. 9 illustrates the clearance between the overlapping portions ofadjacent pusher shoes. Extension 48 of a leading pusher shoe extendsrearward past the trailing edge of a flight and past the leading edge ofthe trailing flight, overlying a portion of edge 8 a and surface 4 a ofthe trailing pusher shoe.

Referring also to FIGS. 11 and 12, pusher pad 38 includes a plurality ofspaced apart, raised ribs 42 configured to contact packages and otheritems on the conveying surface during divert. In the depictedembodiment, ribs 42 are illustrated as being generally uniformly andequally spaced, generally following the contour of upper surface 4 atmounting surface 6. Pusher pad 38 is made of a soft durable material,such as Santoprene, which cushions the contact between the pad 38 andarticles on the conveying surface. Ribs 42 are a truncated pyramid, eachhaving a tip approximately 1/32 inches wide and a base approximately3/64 inches wide. The sides of the ribs 42 are inclined at betweenapproximately five degrees to approximately fifteen degrees. The centerto center spacing of the ribs ranges from approximately 0.14 inches toapproximately 0.18 inches.

Although in the depicted embodiment ribs 42 are all of the same height,adjacent ribs could have differing heights such that a tall set of ribswould first contact a package during divert, deflecting until a shorterset of ribs also contacts the package during divert distributing theforce over additional ribs. For example, the nominal variance betweenadjacent ribs could be 1/32 inches. This effects the acceleration of thepackages, distributing the forces.

As seen in FIG. 12, one of tabs 40 is illustrated in cross section. Eachtab 40 has a respective ridge 40 a which engages a complementarilyshaped ridge 52 a in a corresponding slot 52. The openings of slots 52are shown in FIGS. 13, 14A and 14B. Of course, other configurations maybe used to secure pad 38 to pusher cap 2 a.

Referring to FIGS. 15-22, which correspond to FIGS. 4, 5 and 7-10,corresponding views of the pusher shoe are shown for a round tube typesortation conveyor. Since the construction between the two corresponds,with the differences being in the adaptation for the particular type ofsortation conveyor involved, the round tube type sortation conveyor willnot be discussed in as much detail as the flat slat type sortationconveyor. It is noted that the upper conveying plane of the round tubetype sortation conveyor is defined by the generally planar upper edgesof the round tubes. Additionally, as seen in FIG. 18, the pusher base isformed as a single piece.

Referring to FIGS. 23-32, round tube end cap 68 and bushings 70 areillustrated. Disposed in each end of hollow (filled with foam for noiseabatement) tubes 72 are mounting portions 74 and 76 of respective endcaps 68. Each mounting portion 74, 76 has a respective aligned opening78, 80, which receives bushings 70. Referring also to FIGS. 16 and 17,every other pin 82 of endless chain 84 extends long enough to engage arespective bushing 70 carried by the end caps 68. Pins 82 also carrybearings 86, the outer raceway of which rides along a portion of thesortation conveyor frame, such as in a track, carrying the weight of theslats, pushers, and packages disposed on the conveying surface.

Mounting portions 74 and 76 include a plurality of spaced apart ribs 88which extend above the nominal body exterior wall by approximately 0.015inches, being sized to engage the interior walls of tubes 72 retain theend cap 68 thereto. Lead in chamfer 90 is provided at the distal ends ofmounting portions 74 and 76 to guide mounting portions 74 and 76 intothe respective tubes 72. The overall lengths of mounting portions 74 and76 are preferably long enough to support tubes 72 and provide adequateretention of end cap 68 thereto.

The outer diameter defined by the outer surfaces of radially extendingribs 88 provides up to a nominal 0.010 diametrical interference fit withthe inner diameter of the hollow cylindrical tubes 72.

As can be seen, cylindrical mounting portions 74 and 76 are notconcentric with openings 78 and 80. The centers of mounting portions 74and 76 are offset approximately 5/16 inch vertically above openings 78and 80. This raises the upper surface of tubes 72 and the upperconveying plane to the same level as the slat conveying surfaces 64 andconveying plane 66. This provides the conveying surface at the sameheight relative to the chain pin centers for both the slat and the roundtube sortation conveyors, allowing the commonality between pusher caps 2a and 2 b.

End cap 68 includes a raised boss 92 extending forwardly from wall 94,with openings 78 and 80 therein. As seen in FIG. 29, opening 80 extendsrearwardly for a portion of the length of mounting portion 76, openingup slightly 80 a for the last portion which terminates adjacent distalend 76 b.

Wall 94 also includes two spaced apart openings 96 and 98. Theseopenings provide a location in which to locate a screw driver or otherlever to raise end caps 68 when attached to tubes 72 for disassembly orto otherwise work on the sortation conveyor.

As seen in FIGS. 24 and 28, rib portion 99 extends rearwardly from wall94, interposed between mounting portions 74 and 76, located not tointerfere with tubes 72. Rib portion 99, as illustrated includes spacedapart walls. Depending on the clearances, rib portion 99 may need to beomitted to avoid interference with movement of the pusher base.

Referring to FIGS. 30-32, there is shown bushing 70 having a generallycylindrical body portion 100 and a flange 102. Bushing 70 is sized to bedisposed in a respective opening 78, 80. Although not seen in FIGS.30-32, bushing 70 is keyed to openings 78, 80 in order to preventrotation. Bushing 70 includes centrally disposed cylindrical bore 104,with a chamfer 106, 108 at either end. Bore 104 is sized to receive arespective extension of chain pins 82. It is noted that openings 78 and80 are spaced apart a distance equal to twice the chain link length orpitch. Bushing 70 is made of Delrin®.

Referring to FIGS. 33-38, there is shown another embodiment of an endcap for a round tube type sortation conveyor according to another aspectof the present invention. End cap 110 is similar to end cap 68, withrearwardly (relative to wall 112) extending cylindrical mountingportions 114 and 116, which include a plurality of spaced apart radiallyextending ribs 118. Mounting portions 114 and 116 are longer than thecorresponding portions of end cap 68, extending about 2.25 inches fromthe back of wall 112, and include bosses 120 and 122 internal tomounting portions 114 and 116 into which a fastener, such as a screw(not shown), extending through an opening formed through the wall oftube 72, is secured to hold end cap 110 more securely and reliably tothe ends of tubes 72. Bosses 120 and 122 may include a preformed openingfor receiving a fastener. A self tapping or threading fastener, as wellas any other suitable fastener, may be used.

As seen in FIGS. 34 and 36, the back side of wall 112 includes aplurality of ribs 124, which provide cooling while molding-end cap 110to avoid distortion, and provides additional stiffness.

End cap 110 includes openings 126 and 128 for receiving bushings 130.Openings 126 and 128, respectively, include generally arcuate portion126 a, 128 a. The remaining interior surfaces of openings 126 and 128are generally flat with rounded corners. This profile keys bushings 130in the openings to control the orientation of bushings 130. Its geometrymakes bushing 130 stiffer in the vertical direction than in thehorizontal direction.

Referring to FIGS. 37 and 38, bushing 130 is retained in opening 126 atthe front by flange 132 and at the rear by lip 134 extending from theperimeter of the rear of bushing 130 except across the flat upper edge126 b. There is no lip across flat upper edge 126 b due to spacelimitations as well as to make installation of bushing 130 easier.Bushing 130 includes opening 136 at rear.

FIGS. 39-42 illustrate 20° and 30° right and left hand pusher shoes.Since the pusher caps for each of these shoes are similar, with the onlydifferences being that FIGS. 39 and 41 illustrate right hand pusher caps138 and FIGS. 40 and 42 illustrate left hand pusher caps 140, right handpusher cap 138 will be described, it being understood that left handpusher cap 140 has corresponding construction.

Referring also to FIGS. 43-45, pusher shoe 138 includes generallyvertical mounting surface 142 with a plurality of tabs 144, each havinga respective ridge 144 a for securing a pusher pad to mounting surface142 in the manner previously described.

In the depicted embodiment, portion 142 a of mounting surface 142 isformed at an angle of about 23° relative to portion 142 b and the cap'slongitudinal direction of travel. In this embodiment, the angle ofmounting surface 142 does not establish the divert angle. The pusherpads used with pusher cap 138 are configured either to define a 20° or30° divert angle and mount to a common 23° mounting surface.

Referring to FIGS. 46-50, divert surface 146 of pusher pad 144 includesportion 146 b which is disposed at a 20° angle relative to thelongitudinal direction of travel of pusher cap 138 and, concomitantly toportion 146 a. Pusher pad 144 has a mounting surface 148 disposed at 23°configured to mount to mounting surface 142 of pusher cap 138.

As can be seen, pusher pad 144 is thicker at end 144 c as a result ofthe divergence of the angle of divert surface portion 146 a and mountingsurface 148. For manufacturing purposes, pusher pad 144 is manufacturedas two portions, 144 a and 144 b, and then joined together. Of course,pusher pad 144 may be made of unitary construction.

Divert surface 146 includes a plurality of spaced apart, raised ribs150, similar to the pusher pad ribs previously described herein. Everyother rib 150 has a height (from base to tip) which is lower than thetwo adjacent ribs. As a result of the molding process, ribs 150 do notextend into area 152.

Pusher pad 144 includes portions 154 a and 154 b which extend downwardlybelow the conveying plane of the sortation conveyor, corresponding withportions 142 c and 142 d of mounting surface 142. Portions 154 a and 154b are illustrated without ribs, instead including indicia indicating thedivert angle and direction (right hand). Alternatively, ribs may beincluded on portions 154 a and 154 b.

As seen in FIG. 45, pusher cap 138 includes a plurality of ribs formedin the bottom of pusher cap 138 similar to the ribs of pusher caps 2 aand 2 b. Wall 138 d is interrupted by gap 138 e which is present tomaintain dimensional stability during manufacturing.

FIG. 50 illustrates the openings of slots 156 which receive tabs 144,and secured thereto as described above.

Referring to FIGS. 51-55, the similarities between pusher pad 158 andpusher pad 144 shown in corresponding view in FIGS. 46-50 are apparent.Pusher pad 158 is a 30° pusher pad having divert surface 160 withportion 160 b disposed at a 30° angle relative to the longitudinaldirection of travel of pusher cap 138 and, concomitantly to portion 160a. Divert surface 160 also includes portion 160 c which is disposed at a14° angle relative to the longitudinal direction of travel of pusher cap138 and portion 160 a. As can be seen, pusher pad 158 is thickest whereportions 160 b and 160 c meet. Any suitable angle may be used forportion 160 c. Alternatively, portion 160 b may extend at a 30° angle tomeet an extended portion 160 a.

Pusher pad 160 has a mounting surface 162 disposed at 23°complementarily configured to mount to mounting surface 142 of pushercap 138.

The divert angles are not limited to 20° and 30°, and may be any desiredangle. Any suitable mounting angle may be used which allows the pusherpad diverting surface to define the desired divert angle. In thedepicted embodiment, the mounting angle of the mounting surfaces islarger than the smallest divert angle and smaller than the largestdivert angle which is established by the two pusher pad configurations.Alternatively, the mounting angle could be outside of the range ofdivert angles, with the pusher pad divert surface configuredaccordingly.

The common mounting surface for multiple divert angles may be utilizedindependent of the other features of pusher caps 138 and 140, asdescribed below.

FIG. 56 is an exploded view of the pusher shoe of FIG. 41, configuredfor use with the flat slat type conveyor as shown in FIG. 4. Pusher pad158 is secured to mounting surface 142 of pusher cap 138. Pusher baseassembly 162 includes pusher base 164, of unitary construction andconfigured complementarily to the guide path defined by a slat flight,pusher base plate 166, spacer 168, bearing 170 which is retained andlocated by pin 172. Two screws 174 extend through holes 138 a and 138 cto engage pusher base 164. A single bolt 176 extends through center hole138 b of pusher cap 138, through base 164, plate 166, through spacer 168and bearing 34, threadingly engaging pin 172. Two additional screws 178extend through the two holes 166 a in plate 166, threadingly engagingbase 164. Additional screws 180 are inserted through holes 164 a of base164 into holes 182 (see FIG. 45).

Pusher base 164 includes extension 184 with centrally disposed slot 186.Extension 164 is shaped to fit between the leading and trailing slats ofa flight as well as between the leading and trailing tubes of a flight.Pusher cap 138 (and 140) includes extension 188 which fits into slot186. Similar to pusher caps 2 a and 2 b, surfaces 190 f-h terminate inedges 192 f-h which are disposed below the conveying plane of thesortation conveyor. Lower surface 184 a of extension 184 is generally atthe same level as the lower surfaces of edges 192 f and 192 h. The lowersurface of edge 192 g is slightly higher to fit into slot 186 atopextension 184.

Recessed surfaces 194 a and 194 b are formed in surface 190 of pushercap 138, in between surfaces 190 f, 190 g and 190 h. Recessed surfaces194 a and 194 b are steeper than the adjacent portion of the surface 190c from which recessed surfaces 194 a and 194 b extend, and steeper thansurfaces 190 f-h. Recessed surfaces terminate at edges 194 c and 194 d.The locations and relative angles of surfaces 194 a-b, surface 190 c and190 f-h place recessed surfaces 194 a and 194 b lower than adjacentportions of surfaces 190 c and 190 f-h, inboard of edges 192 f-h, andinboard of the locations where surfaces 190 f-h extend below theconveying surface of the sortation conveyor, in the “cow catcher”configuration described above.

The configuration of recessed surfaces 194 a-b, edges 194 c-d, surfaces190 f-h, and edges 192 f-g allows pusher caps 138 and 140 to be usedwith either a slat type or tube type sortation conveyor, with theappropriately configured pusher based.

Referring to FIG. 43, surface 190 includes recess 190 i, formed as aslight depression in surface 190 c. Recess 190 i is deep enough to havea label or other material secured therein, such that the depth, at leastat the edges, is greater than the thickness of the label or othermaterial. The depth (see FIG. 63) of recess 190I places the label edgesbelow surface 190 c, such that packages which may be directed over thetop surface 190 are unlikely to catch the edge of the label and peel itaway. The label or other material (neither shown) may carry informationuseful for any desired purpose. For example, the information may beindicia, such as a bar code, which uniquely identifies the particularpusher show.

FIG. 58 is a fragmentary perspective view of a sortation conveyor andpusher shoes constructed in accordance with another aspect of thepresent invention. Sortation conveyor, indicated generally at 198,includes a plurality of slat flights 200 comprised of pairs ofrespective leading slats 202 spaced apart from trailing slats 204disposed generally parallel to each other, transverse to the directionof travel (indicated by arrow 206) of sortation conveyor 198. Eachflight 200 carries a respective pusher shoe 208. Each pair of leadingslat 202 and trailing slat 204 are maintained together as a flight 200by a respective pair of end caps 210 disposed at opposite ends of slats202 and 204. As described above, each end cap 210 is supported anddriven by two spaced apart pins extending from the drive chain (notshown).

FIG. 59 is a fragmentary plan view of the sortation conveyor and pushershoes of FIG. 58, showing gaps 212 between within each flight 200between each leading slat 202 and trailing slat 204, defining a guidepath for the pusher base, as described below. When viewed perpendicularto and from above the conveying surface, preferably there is noperpendicular line of sight through gaps 212. Gap 212 is configured toprevent parts of most items being conveyed from extending therethrough,completely or to an undesirable depth.

In FIGS. 60 and 61, which are side views of the sortation conveyor andpusher shoes of FIG. 58 taken along arrow 60 of FIG. 58, with the endcaps at either end of the slats omitted, revealing the shape of eachslat. In FIG. 58, the consecutive flights have been identified as 200 a,200 b, and 200 c for ease of discussion, with the element numbers endingwith the suffix corresponding to that flight's suffix. Within a flight,flight 200 b for example, the spaced apart surfaces 214 b and 266 b ofleading slat 202 b and trailing slat 204 b, respectively, cooperate toform gap 212 b, which defines the pusher shoe guide path. Leadingsurface or edge 218 b of leading slat 202 b is maintained in a spacedapart relationship from trailing surface or edge 220 a of trailing slat204 a of flight 200 a. Leading surface 218 b preferably includes seal222 b which engages trailing surface 220 a of the slat 204 a while theadjacent slat flights travel along the upper conveying surface ofsortation conveyor 198. Seal 222 b may be made of any suitable material,such as extruded from polyurethane. Seal 222 b is disposed in groove 224b which extends the length of leading slat 202 b. Preferably trailingsurface 220 a includes seal engaging portion 226 a, shown as a rib whichextends the length of slat 204 a. Seal 222 b, groove 224 b and rib 226 aare located and dimensioned such that there is the desired contactbetween seal 222 b and trailing surface 220 a, without presenting anyinterference throughout the path of flights 200. While flights 200 aretraveling through the catenary of the return run downstream of the idlergear at the end of the upper run, seals 222 preferably engage trailingsurfaces 220.

Seal 222 b may have any suitable configuration for engaging trailingsurface 220 a and for being held to leading surface 218 b. The retentionportion of seal 222 b may be any suitable configuration. For example,either or both of the bulbous portions of seal 222 b may be hollow. Seal222 b may instead be flat rather than having any bulbous portion. Groove224 b may be omitted and seal 222 b secured to leading surface 218 b byany suitable means, such as by adhesive. Seal 222 b may be carried bytrailing surface 220 a, with the seal retention configuration (depictedin FIGS. 60 and 61 as groove 224) and seal engaging portion 226configured and located as appropriate.

Referring to FIG. 62, there is shown an end view of two adjacent flights200 a and 200 b, with the end caps and pusher shoes omitted. Eachleading slat 202 a and 202 b, and each trailing slat 204 a and 204 binclude respective upper surfaces 228 and 230 which, when on the upperrun of sortation conveyor 198, define the conveying surface incooperation with all other flights on the upper run of sortationconveyor 198. Upper surfaces 228 and 230 are preferably flat asillustrated, although any other suitable shape may be used.

Referring to flight 200 a, which is exemplary of all flights 200 andslats 202, 204, gap 212 a is defined by opposing surfaces 214 a and 216a as a result of the spaced apart relationship between leading slat 202a and trailing slat 204 a. As illustrated, gap 212 a includes offsetportion 232 a, which offsets the gap along its vertical length fromupper surfaces 228 a and 230 a. In the embodiment depicted, offsetportion 232 a has an angle of approximately 33°, and provides strengthto pusher base 244. As can be seen, a vertical line (dashed line 234 a)at the corner of trailing surface 21-a and upper surface 228 a (asillustrated, the rearmost portion of trailing surface 214 a) extends atleast tangent to a portion leading surface 216 a. Leading surface 216 amay extend forward past line 234 a, or if it does not extend to line 234a, the shortfall is preferably small enough to prevent parts of mostitems being conveyed from extending through gap 212 a, completely or toan undesirable depth.

Offset portion 232 a may be any suitable shape, including being arcuate,and may start at upper surfaces 228 a and 230 a, without a verticalportion 234 a. Offset portion 232 a may be in any suitable direction,whether forward or backward. Gap 212 a includes lower portion 236 awhich receives a complementarily shaped portion of the pusher base.Portion 238 a includes recess 240 a, which is included to reduce thewall thickness of slat 204 a for manufacturing purposes.

Slats 202 a and 204 a include a plurality of holes 242 a at each end forreceiving screws which hold end caps 210 to the slats.

Referring to FIG. 63, which is a cross-sectional side view of a pushershoe taken along line 63-63 of FIG. 59, pusher shoe 208 12 comprisespusher cap 138 and pusher pad 144. Any suitable pusher cap and pusherpad may be used, as long as it is shaped complementarily to the specificconfiguration of the slats. The pusher cap may be a right hand, lefthand, or double sided configuration, and be configured for any suitabledivert angle.

Pusher cap 138 is attached to pusher base 244 of pusher base assembly246. Pusher base 244 includes guide portion 248 which is configuredcomplementarily to gap 212 and to cooperate with slats 202 and 204 toallow movement transverse to the conveyor direction of travel. Pusherbase assembly 246 also includes insert 250, bearing 252, and pin 254.

Referring also to FIGS. 64 and 65, pusher base 244 includes uppergenerally planar portion 256 which is configured to have pusher cap 138mounted thereto, and lower portion 248, which is shaped complementarilyto guide path 212. As illustrated, insert 250 is molded integrally withpusher base 244 and includes internal threads which retain threaded end260 of pin 254. Insert 250 includes a plurality of rings 262, each ofwhich has two oppositely facing flat sides 264. Rings 262 retain insert250 longitudinally and flat sides 264 prevent rotation, allowing pin 254to be screwed in. Of course, any suitable configuration may be used.

Pin 254 includes hex flange 266, with the flange portion retainingbearing 252 and the hex portion providing for tightening pin 254 intoinsert 252. Pin 254 includes a slot in which a nylon or other suitabletorque retention substance is disposed. Any suitable torque retentionmeans maybe used, such as applying a locking substance to threads 260,omitting the slot.

Pusher base 244 includes holes 268 a, 268 b and 268 c, which receivethreaded fasteners (one shown in FIG. 63) disposed through holes 138 a,138 b and 138 c in pusher cap 138. Portion 248 includes straight portion270, which necessitates straight portion 234 of gap 212. Straightportion 270 is included in order to use the threaded fasteners to securepusher cap 138 to pusher base 244. If the threaded fasteners areomitted, such as with break away pusher caps, straight portions 234 and270 could be omitted or reduced in length.

Referring to FIGS. 66, 67 and 68, upper portion 256 of pusher base 244includes a plurality of holes 272, each within a respective recess 274.Holes 272 are arranged in pairs of two, with one hole 272 of each ofpair aligning with holes 182 of pusher cap 138 (see FIG. 45). Threadedfasteners 276 are disposed through holes 272 and threadingly engageholes 182 to secure pusher cap 138 to pusher base 244, in addition tothe threaded fasteners disposed through holes 268 a-c. The pairing andspacing of holes 272 allow the same pusher base to be used with anymating type of pusher cap, whether right hand or left hand. The heightof pusher cap prevents the lower row of holes 182 from being locatedcloser to the bottom edge (as seen in FIG. 45). In order to maintain asgreat a span between holes 182, the top row of holes 182 are further offcenter than the lower row of holes 182. This rectangular pattern ofholes 182 is shifted off center in one direction for a right hand-pushercap, and to the opposite direction for a left hand pusher cap. The pairsof holes 272 accommodate both locations.

Lower portion 248 includes boss 278 which surrounds insert 250. Aplurality of arcuate recesses (not shown) are formed in boss 278 aroundinsert 250, which reduces the wall thickness to avoid or minimizedistortion during molding.

Pusher base 244 includes a plurality of spaced apart raised bearingsurfaces 280 and 282. The slats roll forward as pusher shoes 208 arediverted. Bearing surfaces 280 and 282 distribute the loading frompusher base 244 to the slats during the divert. Bearing surfaces 280 and282 may be made of the same material as pusher base 244 and pusher cap138, super tough Nylon ST-801, or may be an insert of suitable material.Bearing surfaces 280 and 282 may be impregnated with an additive, suchas Teflon or molybdenum disulfate. Of course, the entire pusher base 244may be impregnated with an additive such as Teflon, or made of a lowfriction material, to accommodate the sliding motion of the pusherbases.

Referring to FIGS. 69-74, end cap 210 is illustrated having holes 284through which screws 286 are disposed to threadingly engage holes 242 ofslats 202 and 204 to form flights 200. End cap 210 also openings 286which receive bushings 288. End cap 210 includes two mounting portions290 and 292, each of which is shaped complementarily to the interior ofthe respective slat 202 and 204 which receives it, with ribs 294extending outwardly from mounting portions 290 and 292 to engage theinterior of slats 202 and 204. As will be readily apparent, the end capsfor one end of slats 202 and 204 are mirror images of the end caps forthe other ends, since slat 202 is different from slat 204.

Referring to FIG. 74, bushing 288 is retained in opening 286 at thefront by flange 296 and at the rear by lip 298, which extends from theperimeter of bushing 288 except along the flat upper edge, similar tothe retention of bushing 130 as described above.

Slats for slat type conveyors may be made of any suitable material, suchas extruded anodized aluminum. Tubes for tube type conveyors may be madeof any suitable material, such as zinc coated steel.

The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Obvious modifications or variations are possible in light ofthe above teachings. The embodiment was chosen and described in order tobest illustrate the principles of the invention and its practicalapplication to thereby enable one of ordinary skill in the art to bestutilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. It isintended that the scope of the invention be defined by the claimssubmitted with a regular utility application based on this provisionalapplication.

TABLE 1 MATERIAL PROPERTIES OF SUPER TOUGH NYLON Physical Properties:Density 0.0383-0.039 lb/in3 Linear Mold Shrinkage 1.015-0.018 in/inMechanical Properties: Hardness, Rockwell R 89-112    Tensile Strength,Ultimate 6530 psi Tensile Strength, Yield 6000-7500 psi Elongation @break 60-210% Tensile Modulus 261 ksi Flexural Modulus 125-245 psiFlexural Yield Strength 9430 psi Compressive Yield Strength 1900 psiPoisson's Ration 0.35 Shear Strength 8400 psi Izod Impact, Notched 17-20ft-lb/in Tensile Impact Strength 280-550 ft-lb/in2 Parts: End Caps andPusher Caps

TABLE 3 MATERIAL PROPERTIES OF SANTOPRENE Physical Properties: Density0.97 lb/in3 Mechanical Properties: Hardness, Shore A  60 TensileStrength, Ultimate 1000 psi Elongation @ break 400% Compressive Set  23%Parts: All Pusher Pads

1. An endless conveyor comprising a plurality of pairs of slats definingan upper conveying surface, said slats configured to convey articlesdisposed on said upper conveying surface in a forward longitudinaldirection, said pairs comprising: (a) a leading slat and a trailingslat, said leading slat having a trailing surface, said trailing slathaving a leading surface; each said leading and trailing slatscomprising respective upper surfaces which are generally aligned witheach other and define a portion of said upper conveying surface, eachsaid leading and trailing slats comprising respective lower surfaces,said leading and trailing slats having respective lateral lengths whichare approximately equal to each other; (b) a plurality of pusher shoesfor diverting the articles, each pusher shoe of said plurality of pushershoes being carried by a respective pair of said plurality of pairs ofslats; (c) a gap defined between said trailing surface and said leadingsurface extending transverse to said longitudinal direction from saidrespective upper surfaces to said respective lower surfaces, said gapextending laterally along a substantial portion of said respectivelateral lengths; (d) said gap comprising an offset portion.
 2. Theendless conveyor of claim 1, wherein said offset portion is inclinedrelative to said forward longitudinal direction.
 3. The endless conveyorof claim 1, wherein said gap includes vertical portion which is orientedgenerally perpendicular to said conveying surface, said vertical portionbeing disposed between said respective upper surfaces and said offsetportion.
 4. The endless conveyor of claim 1, wherein said a portion ofsaid leading surface extends past a vertical line drawn through wheresaid trailing surface intersects with the upper surface of said leadingslat.